I use this plugin:
to create a variety of "Contact Us"-type forms on more than a dozen WordPress 2.9.1 sites, such as this one:
Sometime between 6 PM last night and 8 AM this morning, all instances of this plugin stopped sending emails. The form is still generated, and inputted data is logged to a text file (if the form is set to do so), but it is not then emailed to the site admin, nor is a confirmation email sent to the user.
I made no changes to my WordPress configuration in that time, nor did I install new, potentially conflictive plugins. I've tried reinstalling DDFM as well. Any idea what could've happened to cause this disruption?